Win8 Downgrade, IDE switch

So, I just built my first pc for gaming and I decided to use Windows 8.1 at first for the OS.  Also, not knowing any better, I used the standard IDE sata option instead of AHCI.  I am running everything on a 120gig SSD and a 1TB HDD.  Right now just about all of my programs and everything are on the hdd while the ssd holds the os.  The problem now is, I am going to install Win7 and get rid of 8 all together, my wife hates it I don't really give a damn, but whatever it's happening.  I want to make the switch while keeping the data and all that where it is, but some other things I want to change are the sata mode to AHCI, also physically having the Users and Program Files(86) folder moved to the HDD.  Right now I just have all the default downloads and libraries over there so it's kind of messy for my liking.  Searching, I've found several different solutions that may work but none that are really tailored to my situation so I'm not sure what would or wouldn't work for me.

Motherboard: GA-97A-DS3P

Kingston 120gb SSD

WD Blue 1TB HDD

I appreciate everyones help... more than you know... 

Man, your question confused the hell out of me. Maybe I don't know enough about SATA but I haven't used IDE in about five years. I think you are over-complicating the situation. If you pop in a 7 disc and create a partition then the OS will be be installed flawlessly. Just give each OS half of your SSD. It won't need a different formatting since they are both Windows partitions. I hope this helped.

Also, about your AHCI problem, Wikipedia of all places says that AHCI only needs to be on before the INSTALLATION of an OS. So if it's not a problem in 8.1 then don't worry about it.